#!/bin/bash #: Description : print formatted sales report ## Build a long string of equals signs divider=== divider=$divider$divider ## Format strings for printf header="\n %-10s %11s %8s %10s\n" format=" %-10s %11.2f %8d %10.2f\n" ## Width of divider totalwidth=44 ## Pri...
string1 != string2两个字符串不相等,返回真值 string1 < string2如果对string1和string2按字母顺序进行排序,string1排在string2前面(即基于地区设定的对所有字母和特殊字符的排列顺序) string1 > string2如果对string1和string2按字母顺序进行排序,string1排在string2后面 图表3: Bash 字符串逻辑操作符 首先,检...
if 先来个实例: x=5; if [ $x = 5 ]; then echo 'x equals 5...case case 其实就是我们熟悉的那个 swich ,但语法形式上有很大的不同。...循环 bash 中有 for 和 while 两种常见的循环体,我们应该都很熟悉。 for 直接上实例,批量修改文件名。...; done 语法其实很明朗: for variable [in word...
if 先来个实例: x=5; if [ $x = 5 ]; then echo 'x equals 5...中的条件语句, Test 是核心,if 和 case 熟悉语法即可。...循环 bash 中有 for 和 while 两种常见的循环体,我们应该都很熟悉。 for 直接上实例,批量修改文件名。...; done 语法其实很明朗: for variable [in words]; do comman...
## COMMAND -[选项列表]ls -alsort -dfu $fileset -- $variable if [ $file -ot $file2 ]then echo "$file is older than $file2."fi \2. 用于stdin或者stdout的重定向的源或目的[dash]. 在tar没有bunzip2的程序补丁时,我们可以这样: bunzip2 linux-2.6.13.tar.bz2 | tar xvf - 。将前面解压的...
How to do string comparison and check if a string equals to a value? How to check if a string is in an array? How to use the Bash ternary operator? How to negate an if condition in a Bash if statement? (if not command or if not equal) How to use the BASH_REMATCH variable with...
test "this string" = "that string" test 1 = 001 test 1 -eq 001 In each case, we usetheechocommandto print the return code of the last command. Zero means true, one means false. Using the equals sign "=" gives us a false response comparing 1 to 001. That's correct, because the...
If you follow those rules then you can avoid accidentally overwriting data stored in environmental variables. You can assign data to a variable using the equals sign (=). The data you store in a variable can either be a string or a number. Let’s create a variable now on the command li...
[student@studentvm1 testdir]$ File="TestFile1" ; if [ -e $File ] ; then echo "The file $File exists." ; else echo "The file $File does not exist." ; fi The file TestFile1 exists. [student@studentvm1 testdir]$ 现在,运行一个测试来判断一个文件是否存在且长度不为 0(表示它包含...
因此,你需要一组更复杂的测试代码 — 为了测试所有的情况,使用 if-elif-else 结构中的 elif 语句: [student@studentvm1 testdir]$ File="TestFile1" ; if [ -s $File ] ; then echo "$File exists and contains data." ; fi [student@studentvm1 testdir]$ ...